How to Repair Your Car's Engine Wiring Harness
When your car's engine wiring harness gets burnt or damaged, an immediate repair is a must. This is due to the fact that the engine wiring harness holds the electrical wirings vital in a vehicle's operation. In order to prevent your car from stalling, or worse, getting on fire, replace a worn engine harness before it leads to vehicle malfunction.
Difficulty level: Moderate
Tools to be used:
- Masking tape
- Shop manual
- Digital camera
- 1/4 -inch socket set
- Screwdriver set
- Jack and jack stands
Step 1: Get your digital camera and capture photos of your wirings' initial positions. Make it detailed and extensive by taking shots at the wiring connections and routing. You can use a masking tape to label the wires for future reference. Then, check and read a shop manual to make out the engine wiring diagram and take note of the color codes of the wires.
Step 2: Unplug the battery from your car and remove the terminal clamps, negative first, with a socket wrench. Hold down the brackets that lock the battery in place and ensure that the battery is placed away from the vehicle, preventing stray sparks while your work on the repair.
Step 3: Detach each wire carefully from the backside of the harness, noting which wire goes where. Disconnect the master, bulkhead connection from where it meets the wiring harness. If there's a rubber cover or screws around the wiring harness, remove them to completely detach the wiring harness.
Step 4: Lift your car using a jack and secure it on jack stands. Disconnect all the wirings underneath the engine. Be sure to isolate non-engine harnesses like the lights and engine fan harness. You don't need to remove such connections.
Step 5: Prepare the new harness wirings by labeling each with a masking tape and following the old wiring connections and routing as shown in the photos you took earlier. Organizing the wires with labels makes the assembly easier and faster.
Step 6: Arrange the installation properly, sorting out tangled wires and understanding how they are connected and routed around the harness. Once you've fully grasped the wiring assembly, you can now proceed with installing the new wires.
Step 7: Lower your car from the jack stands and return the battery. Turn your engine on and check if the harness and its wires are installed correctly.